Hi there,
AbsractFileDriver is using the filename to know the managed class.

It's a cool feature because it's allow loading on-demand.
The problem is, that the filename must be the name of the Class.

It should be great to be able to manually map XML/YAML File description to a Class, like :
$drivers->addMappingFile ( array ( "filename" => "class", "filename2" => "class2") );

This feature is simple to implement, just add a new array inside AbsractFileDriver to know the mapping.
When using the current method with addPaths, parse the folder to get traditional XML/YAML file where filename corresponding to classname and add it to the mapping array.